Computation of highly off-axis diffracted fields using the band-limited angular spectrum method with suppressed Gibbs...

Area of Science:

• Optics and Photonics
• Computational Electromagnetics

Background:

• The angular spectrum (AS) method solves the Helmholtz equation without approximations, but modified band-limited AS methods face challenges with high-off-axis and large-distance propagation due to memory and computational demands.
• Conventional modified AS techniques employ rectangular filters, leading to Gibbs phenomenon-induced ringing artifacts in computed fields.

Purpose of the Study:

• To develop novel angular spectrum (AS) algorithms that enable accurate field computation for wave propagation problems.
• To address the limitations of existing AS methods, particularly regarding computational efficiency and artifact reduction.

Main Methods:

• Proposed AS algorithms utilize smooth band-limiting filters instead of rectangular ones to mitigate Gibbs phenomenon.
• Incorporated techniques to evaluate only nonzero field components, optimizing computational load.

Main Results:

• The developed AS algorithms achieve accurate field computations.
• Significant reduction in computational effort compared to conventional AS methods.
• Elimination of ringing artifacts associated with rectangular filters.

Conclusions:

• The proposed smooth-band-limited AS algorithms offer a more practical and accurate solution for wave propagation problems.
• These advancements provide a superior alternative to current AS methods, enhancing computational efficiency and result fidelity.